"A large number of independent physical and thermodynamical evidence shows that saline water may actually be common on Mars," according to University of Michigan professor Nilton Renno. "Liquid water is an essential ingredient for life. This discovery has important implications to many areas of planetary exploration, including the habitability of Mars."

Renno worded his report very carefully, explaining that the discovery has "important implications," but not outright saying it's proof of water liquid.

Although the temperature in the northern plains of Mars didn't go above minus 15 degrees Fahrenheit while the Phoenix was there for a six-month period in 2008, researchers still believe there could be pockets of water under the surface. The presence of high amounts of salt may have caused the freezing temperature of water on Mars down to minus 90 degrees, which is about 120 degrees colder than Earth's 32 degree freezing temperature for water.

There are numerous spots on Mars that could be salty enough that it's unlikely they'll be able to freeze without the temperature dropping to minus 100 degrees or further, scientists said.

The report is still highly controversial, despite 22 different scientists signing onto the report -- NASA never brought up the discovery, seeing how the evidence may not be enough.

Each discovery of possible signs of liquid water or ice helps researchers hone in on locations space probes and satellites can examine during future missions.